Vitrification is a relatively new approach for cryopreserving biological tissue. Vitrification addresses many of the problems associated with traditional, slow freezing techniques. For example, vitrification avoids cellular damage caused by ice crystal formation, eliminates the need for expensive programmable freezers, and reduces the long period of time needed to complete conventional cryopreservation programs.
The use of vitrification in the clinical setting has broadened with increasing success of the technique using standardized protocols for different cell types. For example, vitrification is currently finding use in the field of reproductive medicine as a means for vitrifying oocytes, embryos and blastocysts. Great successes and improvements in vitrifying these cell types are currently being made.
One important limitation to vitrification techniques is that very rapid heat transfer is needed to effectively cryopreserve tissue. The need for rapid heat transfer requires that vitrification devices be minimally-sized and capable of holding only small tissue volumes. Additionally, the amount of time that a biological tissue sample is exposed to cryoprotectants must be optimized to prevent cyotoxic effects.
Therefore, currently available vitrification devices are optimized for microscopic manipulation of a small number of cells prior to transfer into microvolume devices. Experiments using conventional carriers thus often fail to effectively cryopreserve large tissue volumes or cell suspensions. Effective tissue vitrification requires relatively short but adequate exposure to high concentration of cryoprotectants, ultra-rapid heat transfer during freezing and thawing, and rapid removal of the cryoprotectants immediately after thawing.